Navy ships generate plastic waste at a rate of approximately 0.2 pounds per man per day. This plastic waste has very low density, approximately 1.4 pounds per cubic foot, and approximately 60% of this waste is heavily contaminated with food residue. Historically, all of this plastic waste was mixed with the remainder of the ship's waste and discharged at sea. This method of disposal, however, is no longer used due to its negative environmental impact.
A less environmentally harmful procedure now carried out involves compacting the onboard plastic waste, and storing the compacted waste for disposal upon reaching shore, using a conventional compress/melt waste processor. Such a conventional compress/melt waste processor, as disclosed in U.S. Pat. Nos. 5,411,697 and 5,489,200, to McGraw, et al., compacts the plastic waste inside of a compaction chamber having a hatch door thereon, and heats the compacted waste to a target temperature of approximately 325°–350° F. by cycling resistance heaters until the temperature at the center of the slug (compressed plastic waste) exceeds the boiling point of water. During this processing cycle, the ram continues to maintain the target compaction force. At the end of the process cycle, the control system turns off the electrical resistance heaters and begins cooling the processor.
When the processor reaches a predetermined cooled temperature, the control system stops the cooling process, the ram is retracted far enough to relieve the compaction pressure, and the hatch door is released from the frame by rotating the door about its axis to release a breech lock mechanism. The hatch door is rotated about its hinge axis to open the end of the chamber and the ram is extended to push the completed slug out of the chamber for removal and storage.
However, it was found that the above conventional compress/melt waste processor disclosed in the McGraw, et al. references suffers from various operational and maintenance deficiencies, such as unacceptably long compaction periods, jamming of the compaction ram due to melted plastic wedging between the ram and the chamber walls, jamming of the hatch door when rotating on its axis to free the breech lock at the end of the process cycle, contamination of the machine surfaces due to excessive build-up of food waste, failures of cable and hose under the ram due to poor cable and hose management, failures of non-robust temperature sensors, difficulty troubleshooting because of an overly complex control system, and performance of excessive scheduled maintenance.
In view of the above deficiencies of the conventional processes for plastic waste processing, it is an object of the present invention to provide a plastic waste processor capable of efficiently compacting plastic waste, while also being reliable in terms of operability. In particular, it is an object of the invention to provide a plastics waste processor having a pneumatic compacting means capable of avoiding jamming and sudden release problems encountered with the conventional processors. It is a further object of the present invention to provide a plastics waste processor having a waste containment chamber door capable of being easily and safely opened after processing of plastic waste.
It is yet a further object of the present invention to provide a plastics waste processor having a compaction ram capable of overcoming jamming problems associated with the conventional processors. Further, it is an object of the present invention to provide a plastics waste processor having a washdown system for easy cleaning of the processor after processing, as well as an improved system for efficiently maintaining and protecting moving cable and hoses within the device during processing.